list.subList(1, 3).clear();
    list.addAll(0, Lists.newArrayList("X", "Y", "Z"));
    assertThat(tail).containsExactly("Y", "Z", "a").inOrder();
  }

  public void testSkip_structurallyModifiedSkipAll() throws Exception {
    Collection<String> set = Sets.newLinkedHashSet();
    Collections.addAll(set, "a", "b", "c");
    FluentIterable<String> tail = FluentIterable.from(set).skip(2);
    set.remove("a");

    list.subList(1, 3).clear();
    list.addAll(0, newArrayList("A", "B", "C"));
    assertThat(tail).containsExactly("B", "C", "a").inOrder();
  }

  public void testSkip_structurallyModifiedSkipAll() throws Exception {
    Collection<String> set = newLinkedHashSet(asList("a", "b", "c"));
    Iterable<String> tail = skip(set, 2);
    set.remove("a");
    set.remove("b");